<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>这里是index页面</title>
    <link rel="stylesheet" href="/css/reset.css">
    <style>

        .a{
            background-color: red;
            width: 100vw;
            height: 100vh;
        }
        .b{
            background-color: yellow;
            width: calc(100vw / 750 * 48); /* 适配宽度：48像素在不同浏览器的占比、（100vw视口宽度）除（750物理像素）乘(48像素) */
            height: calc((100vh - 100px));
        }
    </style>
</head>
<body>
    <h1>index.html页面</h1>

    <div class="a">
        <div class="b"></div>
    </div>
</body>
</html>